The subject of endoprosthetic joints has received a great deal of attention over the past several years and has particularly received much attention in recent years due in part to the availability of improved materials inert to human or animal bodies and to improved techniques for manipulating same. However, in spite of such intensive study, the endoprosthetic joints previously available, while in many cases satisfactory to a limited degree, are far from fully satisfactory and intensive work is continuing for the further improvement of such prostheses.
In one particular area, namely that of wrist joints, previous efforts have proven highly frustrating due to the complex nature of wrist joint action and particularly due to the desirability of having substantially universal motion between the hand and the arm but preventing twisting motion between the hand and the arm around an axis projecting from the arm as a substantial continuation of the central axis thereof. In addition, it is essential to provide a joint which can be assembled quickly and easily during the implanting procedure but which after assembly will provide a strong joint capable of withstanding the heavy pressures to which a wrist is subjected during normal use thereof. Accordingly, the objects of the invention include:
1. To provide a prosthesis for a wrist joint which can be assembled or disassembled as needed during the implanting procedures but which will when assembled provide strong resistance against displacing forces.
2. To provide a prosthesis, as aforesaid, which will be of sufficiently simple design as to be readily made by normal manufacturing procedures.
3. To provide a prosthesis, as aforesaid, which can be readily and easily implanted into bone structure on either side of a joint such as a wrist joint.
4. To provide a prosthesis, as aforesaid, which will be strong and sturdy in operation and enable the user to perform all normal wrist functions.
5. To provide a prosthesis, as aforesaid, which closely approximates the normal wrist joint motions.
6. To provide a prosthesis, as aforesaid, which can be used for either right-hand or left-hand implantation without change in the relative positions of the parts thereof.
Other objects and purposes of the invention will be apparent to persons acquainted with devices of this general type upon reading the following specification and inspection of the accompanying drawings.